日治時期台灣於法律體系經歷了很大的轉變，傳統中國法與現代西方化的日本法於此初次交會了。在現代西方法的刑事、民事分類上，台灣人民就刑事事項上，很早便透過律令依用的方式，依照日本刑法的規範；然而在民事事項，尤其是台灣人身分規範的親屬與繼承方面，殖民當局卻始終以「舊慣」來作為國家實體法的依據。如此一來，國家實體法與民間習慣在台灣社會的落實與互動情況就成為筆者欲探討的議題。本文以「通姦罪」為切入點，除了著眼在刑法通姦與民事婚姻的密切相關外，更藉此探討日治時期台灣法律社會的實況。 在討論日治時期台灣「通姦罪」之前，有必要先了解日本殖民以前，台灣社會與明治政府各自對通姦行為的規範，而殖民者與被殖民者這兩種規範下的邏輯思維與文化脈絡，在進入日治時期後，對台灣的通姦規範又有何影響？ 在這個脈絡下，第二章，以清治時期台灣官府制定法與民間習慣下對通姦行為的規範為主題；第三章，以明治政府從現代法經驗出發，探討其在現代西方法繼受過程中，如何將傳統禮教下的「姦」轉化到現代刑法「通姦罪」，與這種繼受經驗對殖民台灣的政策與方針的影響；第四章，以日治時期台灣國家法規範下的通姦罪為主軸，以法院判例分析國家實定法在社會的實際運行情況，特別是西方現代法與台灣民間習慣的衝突；第五章，以內地延長政策下「通姦告訴特例」的實施分析其背後意義；第六章為結論。 / Under Japanese rule，the Legal System of Taiwan encountered a big change from the first intersection of traditional Chinese laws and modern Western-oriented Japanese laws in Taiwan. 　　In criminal matters, Japanese criminal codes were applied directly through orders of the Taiwan Governor. On the other hand, in civil matters, especially in the normative identity, the colonial authorities have always been using "old customs" as the basis of the National Substantive Law. This kind of application brings interesting situations of the interaction between the National Substantive Law and the regional old customs in the Taiwanese society. For Adultery is closely related to both criminal norms and civil norms, it is rather suitable to take Adultery as a start theme for discussing the operation of the law society in Taiwan under Japanese rule. Fisrt ,I have to trace back before 1895 to understand the norm of Adultery in Taiwan during the Qing dynasty and that in Meiji Japan. That would make it much easier to analyze how norm of Adultery actually worked in society of Taiwan under Japanese rule. Therefore, in Chapter II, norms of Adultery in Taiwan during the Qing dynasty were firstly discussed. And in Chapter III, the focus was on norms of Adultery in Meiji Government. Chapter IV is on the norms of Adultery in Taiwan under Japanese rule. Chapter V talked about the exception of Special case of proceedings for adultery. And finally, Chapter VI took the dispute of Adultery in the draft Criminal Code as the conclusion.